However, they apparently have known each other long before they filmed their first scene for the series. Another inside source claims that the two Canadian stars have actually been “friends for years” but “grew closer” on the True Detective set.

In a January 2012 interview with Glamour magazine, Rachel McAdams opened up about her relationship history with costars. Contrary to popular opinion, McAdams made it clear that she did not necessarily find anything romantic about a movie set.

“A set may seem like a good place for romance, but I don’t think it’s very conducive; it’s too distracting. Every relationship I’ve had with a coworker has come after the fact, because you wind up actually spending a lot of time with those people promoting the movie.”

Over the years, McAdams has starred in numerous films that have been focused on her character’s romantic journey in one way or another – such as The Notebook, The Vow, The Time Traveler’s Wife and About Time.

However, McAdams made it clear during that interview that she does not give other people advice on the subject.

“I try not to give advice on love. That’s a slippery slope.”

Over the years, Rachel McAdams has dated numerous movie costars – including Ryan Gosling and Michael Sheen. According to Us Weekly, an insider claims that Rachel even dated Jake Gyllenhaal while they filmed Southpaw together.